Charge density mismatch synthesis of MEI- and BPH-type zeolites in the TEA+–TMA+–Li+–Sr2+ mixed-structure-directing agent system

Nanocrystalline MEI- and BPH-type zeolites, denoted as PST-11 and PST-12, respectively, have been synthesized using both tetraethylammonium and tetramethylammonium ions, the two simplest alkylammonium species, in the presence of Li+ and Sr2+. PST-12 formation is the first example of a combination of forced and multiple cooperative structure-directions in the charge density mismatch synthesis of zeolites.